SharePoint Designer 2013 won't connect to some of my SharePoint 2019 sites (intermittent issue)

Question

I am attempting to open my SharePoint 2019 site on SharePoint designer 2013 but t is now providing an error stating "Microsoft SharePoint Designer does not support editing non-SharePoint sites. "I have checked the event viewer logs on my server with no avail and this site was able to previously be opened in SharePoint designer. I have cleared the following caches:

C:\Users\username\AppData\Local\Microsoft\WebsiteCache

C:\Users\username\AppData\Roaming\Microsoft\SharePoint Designer\ProxyAssemblyCache

C:\Users\username\AppData\Roaming\Microsoft\Web Server Extensions\Cache

This has not resolved anything. I have also attempted to try on other sites in my farm and am able to access some, some of them I'm able to access intermittedly. I have also uninstalled and reinstalled SharePoint Designer and it has not resolved the issue either. No site collection features or site features have been changed since the last time it has worked as well. This issue does not seem to be isolated to modern or classic pages either (it has worked and also not worked with both). Note that my servers are run on windows 2019 and the SharePoint farm is a 2019 farm with a 2019 SQL database.

Please advise, thank you in advance.

Answer 1

Hi @Delaney Troop ,

SPD Error: Microsoft SharePoint designer does not support editing non-SharePoint sites,To resolve this issue, you may want to try the following steps:

1.Check if client integration is enabled in Web Application settings from the Central Admin site.

2.If the above process couldn't help, you may refer to the following steps:

• Press Windows+R > enter regedit;
• Go to HKEY_CURRENT_USER\Software\Microsoft\Office\15.0\Common\Internet\WebServiceCache\AllUsers\office15client.microsoft.com, 
• Delete all the subfolders of the ...\office15client.microsoft.com folder.

WARNING: Using Registry Editor incorrectly can cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that problems resulting from the incorrect use of Registry Editor can be solved. Use Registry Edit at your own risk. 

Note: Microsoft is providing this information as a convenience to you. The sites are not controlled by Microsoft. Microsoft cannot make any representations regarding the quality, safety, or suitability of any software or information found there. Please make sure that you completely understand the risk before retrieving any suggestions from the above link.

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